1. Field of the Invention
The present invention relates to a cooperating connecting structure of a head holder and an ink cartridge for connecting the head holder attached on an ink jet printer for mounting an ink jet head to an ink cartridge. The ink cartridge is removably mounted on the head holder and supplies ink to the ink jet head. In particular, the invention relates to a connecting structure of a head holder and an ink cartridge that reliably prevents damage to an ink filter of an ink supply member mounted on the head holder, if the ink cartridge is mounted in a wrong direction or upside down. The ink supply member connects the ink jet head to the ink cartridge and supplies the ink from the ink cartridge to the ink jet head.
2. Description of the Related Art
There have been various kinds of known ink cartridges for use in ink jet printers. In an ink jet printer capable of printing in colors, for example, black, magenta, yellow and cyan, four separate ink cartridges are generally mounted in the head holder.
A conventional ink cartridge used in this type of ink jet printer will be explained below, with reference to FIG. 12. FIG. 12 is a longitudinal sectional view of the ink cartridge 100. In FIG. 12, the ink cartridge 100 is formed in an approximately rectangular parallelpiped configuration. The ink cartridge 100 comprises an ink container 101 in which an ink-impregnated body G is incorporated. A cartridge cover 103 is joined, for example by welding, to the peripheral edge of the upper opening 102 in the ink container 101. Beneath the front surface 101A (left side in FIG. 12) of the ink container 101, an insertion hole 104 is formed. An ink supply member 109 (described later) is inserted into this insertion hole 104 and is attached to a head holder 106 when the ink cartridge 100 is mounted on the head holder 106. At the rear part of the cartridge cover 103 (right side in FIG. 12), a grip section 105 is formed. This grip section 105 permits gripping of the ink cartridge 100 when the ink cartridge 100 is mounted to, and removed from, the head holder 106.
The grip section 105 is disposed above the rear surface 101B (right side surface in FIG. 12) of the ink container 101. The distance of outward protrusion of the grip section from the rear surface 101B is al as shown in FIG. 12.
The ink cartridge 100 of the above-described structure will not pose mounting problems, so long as it is mounted to the head holder 106 in a proper position and relation to the head holder 106.
The ink cartridge 100, however, is generally small in size, and therefore it is conceivable that the ink cartridge 100 can be improperly mounted. For example, the ink cartridge 100 can be mounted from a wrong direction or upside down onto the head holder 106. Such improper mounting will be explained with reference to FIGS. 13 and 14. FIG. 13 is a longitudinal sectional view showing the ink cartridge 100 mounted in a wrong direction on the head holder 106. FIG. 14 is a cross sectional view of the ink cartridge 100 mounted on the head holder 106.
First, the structure of the head holder 106 will be explained. In FIG. 13, the head holder 106 has a front wall 107 and an integrally formed bottom wall 108. In the front wall 107, an ink supply member 109 comprises an ink hole 109A, which corresponds to the insertion hole 104 when the ink cartridge 100 is properly mounted on the bottom wall 108. At the front end of the ink supply member 109 (right end in FIG. 13), a mesh filter 110 is installed. The mesh filter 110 serves to remove impurities, such as dust in the ink, when the ink is supplied from the ink-impregnated body G in the ink cartridge 100 to the ink jet head 111.
The inward protrusion distance of the ink supply member 109 from the inner surface 107A of the front wall 107 is a2. The protrusion distance a2 is greater than the protrusion distance a1 of the grip section 105, which is formed on the ink cartridge 100. The ink jet head 111 is mounted to the head holder 106 on the front side of the front wall 107, and a head cover 111A is disposed around it.
The head holder 106, as shown in FIG. 14, has a pair of side walls 112, and a plurality of partition walls, or example three partition walls as shown in FIG. 14, formed on the bottom wall 108 between the side walls 112. An ink cartridge 100 is mounted between each pair of partition walls 113.
The peripheral edge of the ink cartridge 100, an opening 101 of the ink container 100 and the cartridge cover 103 are generally joined to each other, for example, by ultrasonic welding. In particular, the surfaces of the ink container 101 and the cartridge cover 104 are welded by shear welding for a substantial amount of weld strength. Also, an outside portion of protrusion 114, which is formed on the underside of the cartridge cover 103, and an inside step section of the peripheral edge of the opening, which is formed in the ink container 101, are joined, for example by welding, as shown in FIG. 14. Therefore, with shear welding, the peripheral edge of the opening of the ink container 101 should be at least 1.5 mm thick. To meet this requirement, a pair of opposite side walls 115 in the ink container 101 of a conventional ink cartridge 100, are 1.5 mm thick throughout. The whole body of the ink cartridge 100, has the substantially same vertical width.
If the above ink cartridge 100 is mounted in an incorrect direction between the side wall 112 and the partition wall 113 in the bottom wall 108 of the head holder 106, the rear surface 101B of the ink container 101 faces the mesh filter 110 of the ink supply member 109, as shown in FIG. 13. At this time, the protrusion distance a2 of the ink supply member 109 extending inward from the inner surface 107A of the side wall 107 is greater than the protrusion distance a1 of the grip section 105 formed on the ink cartridge 100. Therefore, the mesh filter 110 of the ink supply member 109 contacts the rear surface 101B of the ink container 101, consequently damaging the mesh filter 110.
The ink cartridge 100, which is formed with the same width in the vertical direction, can be mounted between the side wall 112 and the partition wall 113, even if mounted upside down in the head holder 106. However, if the ink cartridge 100 is mounted upside down, the mesh filter 110 of the ink supply member 109 contacts the rear surface 101B of the ink container 101, and for the same reasons stated above, results in a damaged mesh filter 110. Furthermore, if the ink cartridge 100 is mounted upside down on the head holder 106, the mesh filter 110 of the ink supply member 109 will immediately contact the front surface 101A of the ink container 101, because the grip section 105 is not present on the front surface 101A. In this case, the mesh filter 110 is also likely to be damaged.
Therefore, if a conventional ink cartridge 100 is mounted in a wrong direction or upside down on the head holder 106, the mesh filter 110 mounted on the forward end of the ink supply member 109 will be damaged.